


fluorescent adolescent

by bronigiri



Category: Haikyuu!!
Genre: Anal Sex, Bottom Miya Osamu, Developing Relationship, Intercrural Sex, M/M, Nipple Play, Separation Anxiety, Sibling Incest, Third Year Miya Twins, brothers with benefits??
Language: English
Status: Completed
Published: 2020-10-20
Updated: 2020-10-20
Packaged: 2021-03-08 19:54:06
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 6,285
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27112219
Author URL: https://archiveofourown.org/users/bronigiri/pseuds/bronigiri
Summary: “‘Samu,” says Atsumu accusingly. “Your roots are growin’ out.”Osamu touches the top of his head absentmindedly. “Oh, I didn’t tell ya? I’m gonna stop dyeing my hair.”
Relationships: Miya Atsumu/Miya Osamu
Comments: 23
Kudos: 486





	fluorescent adolescent

**Author's Note:**

> I’ve always wanted to write about the Miyas in their third year during their emotionally fraught separation stage. With a bonus treat of thighfucking (can you believe it is my first time writing thighfucking?) and Osamu titty appreciation. But don’t be fooled— this is not a PWP, but rather, feelings with a side dish of porn. Enjoy!

The day starts out perfectly fine for Atsumu. There’s a bird chirping at his and Osamu’s window. That, along with the sunlight streaming in, wakes him up a bit earlier than usual. He’s also half-hard, though he can’t remember what he was dreaming of. Probably that girl from his class with the big tits. He’s planning to jack off in peace and quiet when he gets a better idea.

“‘Samu.”

“Nnnrghh.”

He kicks the bunk above him. No response. Kicks it again, and again, until Osamu throws the covers off him in a flurry and pokes his head out over the railing of his bunk.

“If you do that one more time, I’ll rip your dick off in your sleep and throw it in the garbage.”

“G’mornin’ to you too, ‘Samu.” Atsumu grins, unperturbed. “Hey, wanna jack each other off?” 

“I literally _just said—”_

“—that you’d rip my dick off, but then who would ya mess around with? Nobody else wants you. You’d die of blue balls. Come on.” Atsumu pats the spot on the bed next to him. “It’s like five in the morning, we’ve got time.” 

“No. Do it yourself.”

“C’mooooon. I’ll buy ya milk pudding on the way to school.”

Osamu purses his lips in consideration for a long moment. “Fine.” 

Easy. Atsumu gets his dick out while Osamu climbs down the stairs, and has already gotten himself fully hard by the time Osamu sits next to him. The mattress dips under his weight. He lets go of his dick and lets Osamu wrap his hands around it. He bites back a moan at the cold feeling— Osamu must’ve slept with his arms out on top of the covers like a weirdo. But Atsumu’s feeling extra good today, so he’ll let it slide. 

They both warmed up soon enough, anyway. Within another minute Osamu’s got his pants pushed down, too. They still sleep in their matching Vabo-chan pajamas, the ones their mom bought for them at fifteen, two sizes too large so they could ‘grow into them’. Atsumu feels judged by Vabo-chan’s dead eyes as he pushes his brother’s shirt up and shoves it into his his mouth so that he can get better access to his dick. Osamu has nice tits, Atsumu realizes. Definitely nicer than Atsumu’s own. Hm. Maybe his dream _hadn’t_ been about the girl from class after all. 

“Nfrggh,” says Osamu around the fabric of the shirt.

“What?”

Osamu spits out the shirt. A disgruntled Vabo-chan falls back down over his chest. “Don’t tug so hard. It fuckin’ hurts.”

“Fine.” Atsumu slows down. Admires the shape of Osamu’s cock in his hand. And the little sliver of smooth, meaty skin that peeks out over the hem of his pajama pants that have been pushed down to mid-thigh. 

“Hey,” says Atsumu. “I have an idea.”

“No.”

“You didn’t even hear it!” 

“I don’t have to hear it to— _ah—_ to know your ideas always suck.” 

“This one doesn’t, I swear,” Atsumu says hurriedly. “I just— I wanna fuck yer thighs. Can I?” 

Osamu flushes a delightful shade of pink. “...Sure. Do whatever you want.”

“See? Told ya I had good ideas.” He taps Osamu on the shoulder. “Roll over.” 

If only his brother listened to him like this all the time, Atsumu thinks to himself as Osamu lies pliantly on his side. He’s so pretty like this, the nape of his neck laid bare in front of Atsumu for the taking. He latches his mouth there and bites down, earning a yelp from Osamu. Atsumu’s leaked enough precome that he doesn’t need any lube, just goes to town, grabbing hold of Osamu’s hips and thrusting between his legs and _god,_ that feels good. The hot, wet slide against Osamu’s thighs, grinding up against the underside of his brother’s cock— it’s perfect.

“You feel so good,” Atsumu pants into Osamu’s shoulder. He wraps one hand around Osamu’s cock and strokes, inching the other up Osamu’s shirt to fondle at his chest, squeezing against the meaty firmness. 

Osamu jerks under his ministrations. “Nn— _ah—”_

“So good, ‘Samu,” Atsumu growls, “‘s like you were made for me—”

Osamu stutters unintelligibly as he shakes and comes all over Atsumu’s hand. His movements spur Atsumu on even more, and he fucks Osamu’s thighs hard and fast until he too is toppling over the edge. 

He pulls out and watches, entranced, the way that his come paints the inside of his brother’s thighs. He’s still got Osamu’s come on his hand, too. Osamu rolls over, catching his breath, and Atsumu meets his eye deliberately as he puts his come-stained hand into his mouth and licks each finger one by one.

“Gross.” Osamu shudders and makes a face. “Hey, if you’re gonna clean up, you should change the sheets, too.” 

Sure enough, Atsumu’s come has already dripped down Osamu’s thighs onto the sheets and made a mess. Atsumu scowls.

“Why? I already cleaned your come. You clean mine. It’s only fair.” 

“No, you asshole, this is _your_ fault. I keep tellin’ ya to buy condoms and ya never do.”

Atsumu scoffs. “We share everything! If you were gonna catch anything from me, ya would’ve already. Besides,” he tacks on, “it’d be over for us if Mom and Dad found a condom in the trash.” Their parents are away on a business trip for the next week, but they can never be too careful.

Osamu lets out a long sigh. “Fine. Whatever.” He takes the pillow and tosses it onto the upper bunk before stripping the bedsheet off the mattress. “But make that _two_ milk puddings.” 

Atsumu hops in the shower while Osamu does his thing. A few moments later, Osamu yanks the door open and joins in. The cold air hits Atsumu’s wet skin and makes him shiver. 

“Wait your turn, ya asshat.” 

“I’m trying to save _time,”_ Osamu explains, with the condescending tone of a teacher yelling at a five-year-old. “So I can spend more time cooking breakfast for _you,_ you ungrateful pig.” 

Atsumu pushes him. Osamu shoves him back. He nearly slips on the tile and has to brace himself against the wall. By that time Osamu has stolen the shampoo and is lathering it all over his hair. Atsumu yanks it out of his hand and applies it to his own. He fights Osamu for the spot right underneath the shower head. When they’re both done rinsing out the suds, Atsumu gets a good look at Osamu’s hair and frowns. 

“‘Samu,” says Atsumu accusingly. “Your roots are growin’ out.”

Osamu touches the top of his head absentmindedly. “Oh, I didn’t tell ya? I’m gonna stop dyeing my hair.” 

“What?”

Osamu turns off the shower head and shakes his head dry like a dog. “What do you mean _what?_ I don’t wanna dye it anymore, so I’m not gonna. I might cut it short too, keep the bangs outta my eyes. It’s gonna be a problem if I’m gonna be handlin’ food and such, in the future.” 

“You can’t not dye your hair,” Atsumu cries out. “I don’t want to stop dyeing mine! I look good like this!”

“Nobody said you had ‘ta stop dyin’ yours. You can do whatever ya want to yours, and I’ll do whatever I want to mine. It’s _my_ hair.” 

Atsumu just stands there slack-jawed, because what the fuck, the _audacity._ First quitting volleyball to run a restaurant, which, okay, they’ve fought about it already, so it’s water under the bridge. And then getting accepted to a culinary school in buttfuck nowhere— alright, so Kyoto is not buttfuck nowhere, but anywhere without Atsumu is just unthinkable. And now this? At this point he’s raring to punch Osamu in the face repeatedly until he realizes that _they’re not Atsumu and Osamu if they’re not exactly the same but also a little different in the exact same ways._ Which, okay, sounds kind of stupid when he puts it into words, but it _makes sense._

The two of them have always made sense. It’s Osamu who threw a wrench into Atsumu’s life by trying to do his own thing, time and time again. It’s only a matter of time before he fucks off to, like, Mexico and never shows his face here again.

A towel lands on his face. Atsumu catches it, annoyed. During Atsumu’s internal freakout, Osamu has apparently already gotten out of the stall and put on his clothes. 

“Get out the shower, dingus. You’re gonna catch a cold. We got school today, remember?”

Right. School.

* * *

He’s a ticking time bomb of irritability all the way through classes. Ginjima, who sits in front of him, keeps turning around to give him worried glances. 

Practice doesn’t go too hot, either. Atsumu mostly channels his energy into making his serves extra-aggressive and winning some more service aces than usual. But every time Osamu and his stupid hair appear in his field of vision, he gets on edge and fucks up his next serve. Just a barely-there skim over the top of the net on a jump floater, or a too-hard spike serve that goes out of bounds. But Coach and his teammates obviously notice that Atsumu’s having an off day and it’s embarrassing. 

After practice, they cool off, leaning against the gym wall. Osamu reaches for his own water bottle, but Atsumu grabs it first and takes a long, hard swig.

“That’s my bottle,” says Osamu, eyebrow quirked upward in annoyance. “Give it.”

“Nah, I don’t wanna.” Atsumu holds it up and away out of Osamu’s reach.

Osamu narrows his eyes. “Atsumu.” Ooh, using his full first name. How scary. “Give it.”

“No.” Atsumu smirks. And then squares up, expecting Osamu to lunge at him and grab it. “What, ya wanna fight?”

“Fight, fight, fight,” chants Suna, already holding up his phone and ready to film the action.

“No,” says Osamu, deadpan. “I don’t.”

“Why?” Atsumu demands. “Are ya scared? Scared you’ll get yer ass handed to ya?”

“Yeah, Osamu, you should fight him,” says Suna. “I want to put it on TikTok and get famous.”

“I don’t want to fight,” says Osamu. “That’s all.” 

He sounds tired. And that’s the part that makes something inside of Atsumu snap. They’ve _always_ settled things with their fists, and now Osamu wants to be all high and mighty? It’s all wrong. Nothing makes sense anymore. Their balance has been offset and there’s no turning back.

Atsumu throws the water bottle on the ground, turns on his heel and heads out the gym.

The first half of his walk home is sullen and miserable, but then, hit with a sudden stroke of genius, he stops at a Donki on his way home. He emerges with one thousand less yen in his wallet and one tube of greyish-brown hair dye in hand.

Hurrying home before Osamu gets there is the challenge, given that he’s already taken a detour. His muscles are sore from practice and from being tense all day, but he runs for his life anyway, and manages to arrive at an empty house. Quickly, he dashes into the bathroom and squeezes the hair dye into the shampoo, sealing the lid back on innocuously like nothing has happened. 

When he finishes his own shower, Osamu is already home. He’s towelling his own hair dry when Osamu bangs on the bathroom door. 

“Hurry the fuck up.”

Atsumu emerges without even dressing himself just because he knows it pisses Osamu off. Sure enough, Osamu wrinkles his nose at his indecency.

“What?” says Atsumu. “Ya told me to hurry up. Now go shower. It’s all yours.”

He does dress himself eventually, because it’s cold as hell, but when he does he takes Osamu’s clothes just to piss him off even more. And then he lounges on the couch, flicking through the TV channels, waiting for his master plan to enact itself.

In three minutes flat Osamu is storming out of the bathroom, fully dressed. His hair is a satisfying shade of grey-brown, and his face is a fuming red. 

_“What the fuck did you do to my shampoo?”_

Atsumu just shrugs. “You were too lazy to dye yer own roots, and I can’t have ya lookin’ bad standing next to me.”

“I already _told you_ I’m not dyin’ it anymore!” Osamu grabs Atsumu by the collar, face contorted with anger and inches away from Atsumu’s own. “What the hell is wrong with you? Why are you trying to control every goddamn thing I do with my life?”

“Oh, _I’m_ the one tryin’ to control _you?_ ” Atsumu’s chest feels tight all of a sudden. “You’re the one who’s fucking everything up! First ya quit volleyball, and now you don’t wanna dye your hair anymore? Who do you think you _are?_ ” 

Osamu’s jaw is set, his eyes cold. “Fuck if I know, but I sure as hell don’t want to be _you_.” 

He stalks into the kitchen, and dumps the rest of the shampoo down the sink. The murky grey mess churns miserably before being swallowed up by the drain. Osamu walks out of the house and slams the door shut behind him. He doesn’t come back until bedtime.

* * *

The next day at practice is awful. Atsumu never, _ever_ lets his emotions get in the way of his playing. Volleyball is everything to him and he’s nothing if not dedicated to his craft. But somehow, seeing Osamu looking like nothing has happened makes him mad enough to flub a toss, and then two, and then five. And then Oomimi hits the ball into a difficult part of the court, and he and Osamu both dive for the receive and smack into each other, sending each other recoiling backwards and skidding their butts across the gym floor. 

“What the hell was that, ‘Samu?” Atsumu yells. “Do you not have fuckin’ eyes?”

“I moved first,” says Osamu. “You should’ve stopped when you saw me.”

“You did _not.”_

“I _did.”_

At that, Coach blows the whistle and brings the two of them aside to yell at them. At least _that,_ they do together. 

“You’d better get your head in the game. Nationals start in _two days._ Whatever’s going on between you, sort it out.” 

Atsumu bows his head in apology, because he knows enough to admit when he’s fucked up. Osamu bows his head, too, solemnly. 

The walk home after practice is quiet. Despite their usual habits of bickering, they can be comfortable in silence. This is not one of those comfortable silences. As they walk along the river’s edge, Atsumu’s skin crawls with the urge to shove Osamu into the water. It’d be so easy. He’d just have to take one step to close the gap between them, get his hands on Osamu and his stupid hair, and— 

The rock in front of him goes unnoticed until he trips over it and wobbles sideways. Osamu yanks hard at his arm, tugging him away from the water’s edge and back onto the safety of the path.

“Jeez,” says Osamu exasperatedly. “Are ya blind? Pay attention to your surroundings.” 

Atsumu blinks. After a moment, he says, “You could’ve pushed me in.” 

“I _should’ve,”_ Osamu laments, though his eyes are soft. “Living with you is a fuckin’ test of self-restraint.” 

“‘Samu,” says Atsumu. Something dangerous climbs up his throat, inching up to the back of his tongue, itching to be said. “I—” 

Osamu just looks at him. Atsumu trails off, and shakes his head. 

“Nothing. Race ya back home?”

“Save yer energy for Nationals, idiot.” 

Atsumu runs home anyway, and Osamu, inevitably, follows. 

* * *

In the blink of an eye, they’re at Nationals. It always feels surreal, arriving at the place you’ve been thinking about for ages and finding that it’s just as big and spacious as you remembered. As perfect a space as any to make history. 

Inarizaki is one of the seeded schools again, so their first game is on day two. Their first match is against a no-name school that unexpectedly beat out Nekoma, but no matter— they won’t last against Inarizaki. 

The opposing side serves, and Riseki gets the dig, giving the ball a nice, high arc. Atsumu gets his foot under it in a perfect first step. There’s a brief moment, as the ball hovers in the air in slow-motion, when Atsumu contemplates setting to somebody else. He and Osamu haven’t exactly worked through their rough patch. But maybe it’s muscle memory that compels him to set to his twin anyway. And it works. That first quick they pull off, something they took from Karasuno’s freak duo and made their own, scares the shit out of their opponents. The look on their first-year middle blocker’s face carves itself into Atsumu’s memory as he high-fives Osamu. It’s as good a piece of proof as any of their strength, no matter what comes between them. Evidence that all those years they've spent being constantly in sync with one another don’t just go away overnight. 

It’s not a resolution, but Osamu’s palm is solid against his own. They still have things to work out, but for now, nothing matters beyond the lines of the court and the feel of the ball in their hands. 

Round three takes a toll on them— hell, it’s Karasuno, after all. Atsumu still remembers pointing his finger at Hinata Shouyou and proclaiming that he would set for him one day. Back then, he hadn’t yet known that Osamu was planning to quit. He’d gone home and started building his dream team in his head, adding Hinata to the roster, along with Osamu of course, and that freaky wrist guy from Itachiyama, and so on. Life was good. Ignorance was bliss. And then Osamu had dropped that bomb and blown up all of Atsumu’s future plans. 

Still, knowing what he does now, it feels _right_ to have Osamu next to him as they squeak out that win against Karasuno, like one last sweet piece of payback. Covered in sweat and panting for breath, he huddles in a team hug with his brother shoved tight against his side, not knowing what comes next, but not willing, never willing, to give this up.

* * *

They beat out Itachiyama, and therefore Sakusa, during the quarterfinals. It’s Atsumu, Osamu, and Suna at the net, a towering block over a cross-shot aimed a second too late, that sends Sakusa’s spike hurtling back at his team. 

“I’ll set for you someday,” Atsumu tells Sakusa, who looks at him like he is a piece of toilet paper stuck to his shoe.

“You’ve gotta stop sayin’ that to people,” says Osamu. “It freaks them out.”

They overtake Fukurodani in semi-finals, another game well played. Even without the really loud ace, their setter is a menace, with the flexibility to adapt his play style to others and stay calm all the while. 

“You could take a page or two from his book,” Osamu tells Atsumu, and Atsumu tells him to _shove it,_ because _Inarizaki_ won, alright. 

Finals has Atsumu’s heart pumping so fast he thinks it’ll explode out of his chest. It’s Kamomedai, after all. He watched them take down the crows last year. His fingers _itch_ to play as the players line up, and that deep-seated hunger for a good game, for victory, takes full hold of his body as he squares up for what feels like the longest, and shortest, game of his life.

Beating Kamomedai by getting through their formidable freaking block _has_ to be the best possible way to win. Nothing can compare to that feeling of knowing your opponent has worked their ass off to hone their specialty, and that you, too, have worked just as hard to break right through it, cracking that wall right down the center. 

More than that, though— it feels poetic that his set and Osamu's spike are what get them the win. The sheer joy in Osamu’s eyes, the way his whole face lights up as he crashes into Atsumu for a tight hug— Atsumu doesn’t think he will ever forget that feeling. Years later, when the clouded surface of the trophy collects dust on his shelf, it will be this moment that etches itself, crystal clear, in his mind.

* * *

High on adrenaline and dizzy with joy, Atsumu zones out in the locker room, replaying every glorious moment in his mind like a film reel. When he comes to again, only him and Osamu are left in the locker room, and Osamu is jabbing him in the side unnecessarily hard with the bony part of his elbow. 

“What’re ya zonin’ out for? Everyone else is gone, so hurry up. Let’s get goin’.” 

“We won,” says Atsumu stupidly.

“Yeah.” 

“We _won,_ ‘Samu. We did it.” 

“Yeah, ‘Tsumu,” Osamu smiles. “We did it.” 

Atsumu is high on the joy of victory, and the familiar comfort of pulling off the impossible with Osamu at his side. So it doesn’t truly hit him, until now, the bittersweet fact that it’s the last game he will ever play with Osamu.

Osamu looks at him with this wry little smile, tilting up the corner of his mouth as he looks at Atsumu with— with pride, with affection, and all Atsumu can think about is whether Osamu could possibly know how much all of this _means_ to him. 

There’s a whole typhoon raging inside him, the twin sensations of joy and sorrow twisting together until one is indistinguishable from the other, the way that it so often is with Osamu these days. And it hits him that there’s something he absolutely has to do before their days run out.

He pulls Osamu in by the collar of his shirt, and kisses him. 

Osamu’s mouth is warm against his own, surprisingly soft. Atsumu has to wonder why they’ve never done this before when it feels this good, this _right._ He presses up closer against Osamu, pushing him up against the lockers, and kisses him harder, more insistently, tongue dragging along Osamu’s bottom lip— Osamu opens his mouth on instinct and lets Atsumu roam his tongue inside for only a brief moment before letting out a choked gasp and pushing him away. 

“‘Tsumu,” says Osamu breathlessly. His hair is a mess, his lips are pink, and he looks— bewildered. Atsumu’s vision spins with the newness of it all. “Why—?”

“I wanted to,” says Atsumu. “Do you want to?”

Osamu holds his gaze. As if something clicks into place, a newfound hunger blazes in his eyes, and this time it’s Osamu who grabs Atsumu and crashes their lips together again. 

The rush is intoxicating. The feel of Osamu’s hands, warm and solid, pressed against his abdomen, trailing up and leaving hot fire in its wake. Osamu’s mouth on his own, hot and insistent and somehow still gentle, inquisitive. Whatever Osamu is trying to say, Atsumu thinks he understands: that Osamu wants this too, wants _him—_

A loud knock sounds on the door. It’s Aran, who, along with Kita, has come to watch their former team. 

“Hey, are you two done yet? We’re all waitin’ for ya.” 

Atsumu scrunches his eyes shut and clenches his fist to will all the blood away from his recently hard dick. He loves Aran like a brother— okay, maybe not the best comparison to make right now— but _fuck,_ he is burning with the red-hot frustration of a thousand suns.

Osamu clamps a hand over Atsumu’s mouth, running damage control, knowing he won’t be able to talk without sounding fuming mad. “Yeah, almost. Sorry ‘bout that.” 

“‘Kay. We’re gettin’ yakiniku, so hurry up!” 

Atsumu looks at Osamu inquiringly, and Osamu fixes him with a _look,_ one he knows very well. _To be continued._

* * *

It’s dark out when they finally get home. Their parents, who watched the whole thing on television, call Osamu’s phone and demand to be put on speaker so they can congratulate them and shower them with praise. It’s nice, Atsumu has to admit. A little embarrassing to be fawned over at this age, but still nice. He wonders how things will be after Osamu moves out, and Atsumu himself leaves the nest to go where the V-league takes him. He got offers at Nationals from several Division Two teams. The one that intrigues him most might be the MSBY Black Jackals— Bokuto’s there too, and he hears they’re well on the way to Division One. 

He’s as excited about the future as he is anxious. But he pushes all that aside for the moment, in favour of the _thing_ burning between him and Osamu that hasn’t yet fully been explored. When Osamu hangs up the phone, they exchange a wordless look that says everything they need to say. In unison, they hurry towards their bedroom, and fall into one another on the bottom bunk, pulling each other close, mouths colliding in a heated kiss. 

It’s just as good as the first time. Better, now, because they have all the time in the world. Atsumu slides his hands under the hem of Osamu’s shirt, letting his fingers roam freely over the soft skin there as he deepens the kiss, presses Osamu back against the bed and devours as much of him as he can. Until it’s not enough, and the clothes between them get annoying, so he tugs Osamu’s shirt off over his head, and lets Osamu do the same to his own. A hesitant, questioning hand rests on the hem of Atsumu’s pants, and Atsumu nods. They ditch their pants and boxers, for once not arguing about whose fault it is that the room is so messy, as both their clothes land in a heap on the floor.

They’ve had a lifetime of moving in unison on the court, and this too is no different. In heated, perfect synchronization, they rock against one another, back and forth, and back and forth. Atsumu lets out choked-off little gasps every time Osamu rubs against him _just right,_ and Osamu gladly swallows up his noises, until Atsumu gets a hand around both their cocks and Osamu _whimpers_ into his mouth. It’s Atsumu’s turn to grin, giving Osamu’s bottom lip a parting swipe with his tongue, before shifting down the bed to kiss along the smooth skin of Osamu’s neck. Atsumu’s mouth travels along the junction of his neck and shoulder, down to the dip of his collarbone, memorizing every familiar edge and curve of his twin’s body, and relishing the newness of the sounds Osamu makes at each stop along the way. 

When Atsumu gets to Osamu’s chest, he can’t resist leaving a bite in the firm, supple flesh there. Osamu _yelps,_ body jerking like he didn’t expect it, which is crazy, because there’s no way Osamu doesn’t know how often Atsumu dreams of taking those tits into his mouth. 

“What?” says Atsumu. “Ya don’t like it?” Even as he asks, his tongue is swirling along the tip of Osamu’s nipple. It’s fun, teasing his brother like this. A different kind of teasing than the kind they usually partake in. Outside the bedroom he might be met with a fist in the face, but now Osamu brings his fist up to his own mouth and bites against his knuckles to keep from making a sound.

“Didn’t say that,” Osamu says, muffled against his hand. 

“Then I’ll keep goin’,” says Atsumu, not without glee. He takes Osamu’s other nipple into his mouth, takes his time sucking and licking until it’s all perked up, then leaves bites around it until Osamu is whining into the back of his hand and kicking at the bedsheets. A surge of _want_ rushes over Atsumu, so powerful it nearly knocks his breath out of his chest. It’s always been about getting himself off, and Osamu just happened to always be _around._ Or so he thought. Now, though, it feels like nothing matters but the parts of him that are touching Osamu. Like he wants to meld the two of them together, and never be apart. He’s so dizzy with this newfound feeling that it takes him a moment to process that Osamu has pushed him off and is now panting heavily.

A sharp pang hits his chest. Does Osamu not want—? They’ve always wanted the same things, but things are different now, and— 

“Stop that,” Osamu mumbles. “If ya keep goin’ like that I’m gonna come.” 

Still confused, Atsumu says, “Isn’t that the point?”

A flush creeps over Osamu’s cheeks. “I just thought— I wanted us to come together.”

 _Oh._ Relief and something else flood over Atsumu instantaneously. Before he knows it he’s sliding his hands along Osamu’s thighs, spreading them apart. Osamu really _is_ hard, looking like he’s right on the edge of losing control, and if Atsumu thinks about it, maybe there _is_ another thing they haven’t tried yet that he wants to before he loses his chance.

“‘Samu, can I—” Atsumu swallows thickly. “Can I fuck you?” 

“Yeah,” says Osamu breathlessly, without so much as a beat of hesitation. 

The strange new feeling is back, making Atsumu’s head spin as he reaches under the bed for the lube. It’s like— like getting a service ace, or giving a perfect toss. Like everything falling into place. He pours some over his fingers, and nudges Osamu’s thigh apart with his free hand, before prodding one finger into his entrance.

The sound Osamu lets out is quiet. Between the two of them, Atsumu’s always been louder, but that only makes it all the better when Atsumu draws the hottest sounds out of Osamu, a side of his brother no one else gets to know. He thrusts his finger, slowly getting Osamu to relax again before inserting a second, and then by the third Osamu’s trembling with either the exertion of holding himself back, or the anticipation. Maybe another day Atsumu would have taken pleasure in fingerfucking Osamu through his orgasm, but today he just _wants,_ pure and simple, to be inside of him, to hold him closer than ever before. 

He lines himself up against Osamu's hole and pushes in slowly, letting himself drown in the indescribable pleasure. “Fuck,” he curses out, holding as still as he can to let Osamu get used to the feeling. “God— it feels _so good,_ you feel so good—” 

“Then _move_ already,” Osamu says, hooking his legs around Atsumu to draw him in closer. And Atsumu doesn’t have to be told twice.

He thrusts hard, chasing the pleasure blindly, overwhelmed by the perfect, tight heat of Osamu around him. Burying his head in the crook of Osamu’s neck, he gasps out, “‘Samu, ‘Samu— oh, _fuck,_ you feel _incredible.”_

Osamu’s moans grow more high-pitched as Atsumu picks up speed, gripping his brother’s hip with one hand and propping himself up with the other elbow, driving deeper and searching for the better angle. In this, too, they work together— Osamu shifts his legs up higher around Atsumu’s shoulders until Atsumu finds the spot that has Osamu yelling and throwing his head back. 

The sweat is sticky where their bodies are joined, and where their foreheads are pressed together. The bed is creaking precariously. But all that matters is the moment where the two of them, not once taking their eyes off each other, fumble for the other’s hand and hold it tightly in their own.

“I’m close—”

“I’m gonna come—”

Osamu tips over the edge first, head falling back as his body shakes with pleasure. Atsumu follows, catching Osamu’s lips in a wet, messy kiss as he comes inside of Osamu, so hard he nearly sees stars.

They catch their breaths, limbs still caught together in positions that slowly grow from intimate to awkward as the post-coital high fades away. Osamu is folded kind of like a pretzel, which can’t be all that comfortable. Atsumu pulls out reluctantly, and Osamu moans softly as the come spills out of him, onto the bedsheets.

“Again?” Osamu grumbles. The familiar, annoyed furrow in his brow is back. “You’re changin’ the sheets this time. And get off me, it’s gross.” 

Atsumu rolls off of his brother, lying flat on his back so that two of his limbs dangle off the edge. Atsumu has always known that they have grown too big to share this cramped space. But even so, whenever Atsumu couldn’t sleep or Osamu had a nightmare, they’d worm their way under the other’s blanket and sleep like that, curled up together. Physical discomfort didn’t matter, for just being close to each other made them feel so much more at ease.

Well, that was the way it used to be.

Atsumu gets off the bed. His muscles are sore, both from finals and from what they did just now. But he forces himself to walk over to the bathroom and get a towel anyway. He returns with it in hand. 

“I’ll change the sheets later. Lemme clean ya up first.” 

Osamu doesn’t object, just lies still as Atsumu wipes up the mess they made. It’s quiet, except for the occasional pained noise when Atsumu rubs too hard at Osamu’s sensitive skin. Until Osamu speaks up.

“What’re you thinking about?”

Atsumu blinks. “Huh?” 

Osamu takes the towel from Atsumu’s hand, tosses it aside, and sits up straight to look Atsumu in the eye. “Ya never had trouble speakin’ your mind, so why hold your tongue now?” He prods at Atsumu’s cheek with a finger. “C’mon. Out with it.”

“Nothing,” Atsumu says defensively, before realizing that Osamu’s right. For better or for worse, there’s no way he can hide anything from his twin. “It’s just. We’re not gonna do this anymore, are we? After— after you’re gone.” 

“Are ya talkin’ about volleyball, or…?” 

“Everything! We did everything together! And now—” Atsumu’s voice cracks. “You’re leavin’ me behind. You don’t need me anymore.”

It's been a long time coming, but saying it still hurts. His eyes burn. His chest aches, like he’s torn himself open and bared the insides for Osamu to see. It’s hard to breathe. He looks up at Osamu pleadingly. And Osamu looks at him, really looks at him. His eyes go from confused, to understanding, to something soft and maybe even tender.

“‘Tsumu,” he says. “Do you know why I wanted to work in food service?” 

Atsumu sniffles. “‘Cause you eat like a pig.”

“No, you fuckin’ _idiot._ I’m trying to be _nice_ to ya, would ya just let me— oh, stop that. Stop it.” 

Osamu wipes the tear trickling down Atsumu’s cheek with a thumb. With his other hand on the nape of Atsumu’s neck, he brings him in close and presses their foreheads together.

“Listen, alright? I’m only gonna say this once. All that time I spent makin’ lunch for the two of us, thinkin’ about what kinds of ingredients I should use so that we could eat a balanced diet, and build muscle, and have it still taste good. It was tiring at first, but then it got… kinda fun. I’d watch you eat, and see that look on your face and just think about how happy it made ya. And I got addicted to that feeling. Of makin’ something with your own hands, and sharin’ it with the people you love.” 

Something impossibly warm unfurls in Atsumu’s chest, something that lifts a weight he didn’t know was there. Seeing that look on Osamu’s face, his worries dissipate, leaving only the desire to wrap his arms around his brother and hold him close. So he does just that. 

“‘Samu,” he sniffs into Osamu’s shoulder.

Osamu wraps his arms around him, too, and nuzzles his head against Atsumu’s own. 

“So don’t go thinkin’ stupid things on your own anymore,” says Osamu. “Alright?” 

Atsumu nods. 

“I’m gonna miss you,” he says softly into the crook of Osamu’s neck.

“...Me too.”

Atsumu sniffles again, wipes his eyes with the back of his hand, and pulls back. 

“So, since I’m like, the whole inspiration behind your onigiri shop, you’re gonna name it after me, right?”

It’s a crack at a joke to lighten the mood, but Osamu doesn’t laugh, only fidgets. 

“I guess,” says Osamu, cheeks blotted with pink. “I mean— I was thinking maybe something with both our names.”

“Miya,” says Atsumu. “Like, ‘Onigiri Miya.’” 

Osamu’s eyes light up. “That’s good. Yeah, I like that. I like that a lot.” 

Atsumu grins. “I get fifty percent of the profits, right?” 

“Sure, if ya give me fifty percent of your pro athlete salary.”

Atsumu wrinkles his nose. “Greedy asshole.” 

“Takes one ‘ta know one.” 

They lie in contented silence for a while, before Atsumu can’t resist speaking up again, just to hammer the point home.

“Just so ya know, you’re not gettin’ rid of me,” he says. “I’m gonna take the train to yer school every damn week. I’m gonna tell all yer new friends all the embarrassing shit you did when you were a kid. Like how you wet yer bed till you were nine.” 

“Sure,” says Osamu without missing a beat. “I’ll tell ‘em you did it till you were ten.”

“Oh, _fuck_ you!”

Osamu’s eyes are full of mirth as he grins. But when he looks at Atsumu again, his eyes are soft.

“Hey,” he says. “If you want to— if you want to keep doin’ this. You know, you and me, this whole thing. You could stay over at my new place whenever you want. And we could—” 

“Make out?”

Osamu nods.

“Have sex?”

Osamu nods again.

“Hold hands?”

Osamu flushes. “Just not in public.” 

“So we can have sex in public?”

“No!” Osamu groans. “Stop missing the point on purpose.”

Atsumu kisses him, soft and sweet and slow. How could he not? 

When he pulls away, he says, “Yeah. That sounds like a plan.” 

**Author's Note:**

> Thanks for reading! Feel free to hmu on [Twitter](https://twitter.com/tsumusamuwu).


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